Energy firms fear that plans to force them to share data with rivals are a 'spammers' charter' which would leave customers wide open to the risk of fraud.

The Competition and Markets Authority is expected to suggest that energy companies should have to hand over customer details to rivals in order to allow them to make direct contact with a view to offering better deals.

The suggestion has horrified energy firms which – in common with all commercial organisations – guard customer data jealously. One senior energy executive said: 'This would be not just an industry issue, but a broader social issue, too.

Alert: Details of customers could be leaked, according to energy firms

'Sharing customer information could not only fall foul of data protection rules, but it could also leave customers wide open to spammers who send out fake letters en masse trying to con money out of them.'

There are suggestions that the risk of fraudsters accessing the information could be minimised if customer data was dealt with by the industry regulator Ofgem.

The CMA has been conducting a review of the energy sector and is due to publish its provisional recommendations on Thursday.

Share this article

HOW THIS IS MONEY CAN HELP

It is understood that energy firms are ready to accept the introduction of a price cap for the most vulnerable customers.

The idea was floated by the CMA in an earlier version of its report last year.

An energy source said: 'There may be some support within the industry for such a move, though that might depend on how they define 'vulnerable'.'

The CMA had originally proposed that a default tariff could be created for customers who do not switch to fixed price contracts, which are generally cheaper. However, three-quarters of customers are on more costly standard variable tariffs and this led to intensive lobbying from the energy industry.